Emission of Highly Activated Soot Particulate—The Other Side of the Coin with Modern Diesel Engines

Frank, Benjamin; Schuster, Manfred Erwin; Schlögl, Robert

doi:10.1002/anie.201206093

Cited by 74 publications

(37 citation statements)

References 21 publications

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“…Boreskov and co-workers [24] proposed that for metal oxide catalysts the oxygen bond strength on the catalyst surface, as measured by the heat of oxygen chemisorption, is a determining factor for activity in reactions involving oxygen activation. This has been observed to be the case in oxygen activation reactions such as 16 O 2 / 18 O 2 isotopic exchange [24] and oxidation of CH 4 [24], C 3 H 6 [25], H 2 [24][25][26][27] and CO [28][29][30]. The activity in the catalytic oxidation of CO on thin metal oxide films has also been correlated to the activation energy for oxygen desorption [31], which scales with the heat of chemisorption.…”

Section: Introductionmentioning

confidence: 95%

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Importance of the oxygen bond strength for catalytic activity in soot oxidation

Christensen

Grunwaldt

Jensen

2016

Applied Catalysis B: Environmental

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The oxygen bond strength on a catalyst, as measured by the heat of oxygen chemisorption, is observed to be a very important parameter for the activity of the catalyst in soot oxidation. With both intimate contact between soot and catalyst (tight contact) and with the solids stirred loosely together (loose contact) the rate constants for a number of catalytic materials outline a volcano curve when plotted against their heats of oxygen chemisorption. However, the optima of the volcanoes correspond to different heats of chemisorption for the two contact situations. In both cases the activation energies for soot oxidation follow linear Brønsted-Evans-Polanyi relationships with the heat of oxygen chemisorption. Among the tested metal or metal oxide catalysts Co 3 O 4 and CeO 2 were nearest to the optimal bond strength in tight contact oxidation, while Cr 2 O 3 was nearest to the optimum in loose contact oxidation. The optimum of the volcano curve in loose contact is estimated to occur between the bond strengths of α-Fe 2 O 3 and α-Cr 2 O 3 . Guided by an interpolation principle Fe a Cr b O x binary oxides were tested, and the activity of these oxides was observed to pass through an optimum for an FeCr 2 O x binary oxide catalyst, which exhibited a rate constant at 550 °C that was 2.3 times higher than the one for pure α-Cr 2 O 3 and 29 times higher than the one for pure α-Fe 2 O 3 .

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Section: Introductionmentioning

confidence: 95%

“…Soot particles in the exhaust from diesel vehicles are likely to cause lung cancer and to affect the climate both locally and globally [1][2][3][4][5][6]. The soot particles are therefore typically removed from the exhaust gas by filtration through a ceramic filter [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Christensen

Grunwaldt

Jensen

2016

Applied Catalysis B: Environmental

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“…Soot particles in the exhaust from diesel vehicles are likely to cause lung cancer and to affect the local climate and air quality [1][2][3][4][5][6]. For that reason the soot particles are typically removed from the exhaust Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Visualizing the mobility of silver during catalytic soot oxidation

Gardini

Christensen

Damsgaard

et al. 2016

Applied Catalysis B: Environmental

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The catalytic activity and mobility of silver nanoparticles used as catalysts in temperature programmed oxidation of soot:silver (1:5 wt:wt) mixtures have been investigated by means of flow reactor experiments and in situ environmental transmission electron microscopy (ETEM). The carbon oxidation temperature was significantly lower compared to uncatalyzed soot oxidation with soot and silver loosely stirred together (loose contact) and lowered further with the two components crushed together (tight contact). The in situ TEM investigations revealed that the silver particles exhibited significant mobility during the soot oxidation, and this mobility, which increases the soot/catalyst contact, is expected to be an important factor for the lower oxidation temperature. In the intimate tight contact mixture the initial dispersion of the silver particles is greater, and the onset of mobility occurs at a lower temperature which is consistent with the lower oxidation temperature of the tight contact mixture.

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“…In the last years, as a consequence of the increasing awareness of the public of the potential cytotoxicity of soot particulates, as recently confirmed by the World Health Organization (WHO), the legislative body has imposed increasingly more strict emission levels. The modifications made to the diesel engine to fulfill the low emission standard have essentially changed the morphology and surface functionalization of the soot drastically increasing the chemical reactivity of the carbon surface, thus making it more cytotoxic [17, 18]. Like airway epithelial cells, the epidermal cells, as constitutive elements of the outermost barrier in direct contact with air pollutants, are among the cell populations most exposed to chemical pollutants, including DEP.…”

Section: Introductionmentioning

confidence: 99%

Proinflammatory Effects of Diesel Exhaust Nanoparticles on Scleroderma Skin Cells

Mastrofrancesco

Alfè

Rosato

et al. 2014

Journal of Immunology Research

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Autoimmune diseases are complex disorders of unknown etiology thought to result from interactions between genetic and environmental factors. We aimed to verify whether environmental pollution from diesel engine exhaust nanoparticulate (DEP) of actually operating vehicles could play a role in the development of a rare immune-mediated disease, systemic sclerosis (SSc), in which the pathogenetic role of environment has been highlighted. The effects of carbon-based nanoparticulate collected at the exhaust of newer (Euro 5) and older (Euro 4) diesel engines on SSc skin keratinocytes and fibroblasts were evaluated in vitro by assessing the mRNA expression of inflammatory cytokines (IL-1α, IL-6, IL-8, and TNF-α) and fibroblast chemical mediators (metalloproteases 2, 3, 7, 9, and 12; collagen types I and III; VEGF). DEP was shown to stimulate cytokine gene expression at a higher extent in SSc keratinocytes versus normal cells. Moreover, the mRNA gene expression of all MMPs, collagen types, and VEGF genes was significantly higher in untreated SSc fibroblasts versus controls. Euro 5 particle exposure increased the mRNA expression of MMP-2, -7, and -9 in SSc fibroblasts in a dose dependent manner and only at the highest concentration in normal cells. We suggest that environmental DEP could trigger the development of SSc acting on genetically hyperreactive cell systems.

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Emission of Highly Activated Soot Particulate—The Other Side of the Coin with Modern Diesel Engines

Cited by 74 publications

References 21 publications

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Importance of the oxygen bond strength for catalytic activity in soot oxidation

Visualizing the mobility of silver during catalytic soot oxidation

Proinflammatory Effects of Diesel Exhaust Nanoparticles on Scleroderma Skin Cells

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